Grate bar lock



Dec. 21, 1943. J; KW2 HALL s 2,337,1Q0

' GRATE BAR LOCK 'Fi1ed`sep`t- 27, 1941 2 sheets-sheet 1 INVENTOR Dec.21, 1943. J. w. HALL 2,337,100

GRATE BAR LOCK Filed Sept.^27, 1941 2 Sheets-Sheet 2,

Patented Dec. 21, 1943 GRATE BAR LOCK John W. Hall, Conemaugh Township,Somerset County, Pa., assigner to The National Radiator Company,Johnstown, Pa., a corporation of Maryland Application September 27,1941, Serial No. 412,629

4 Claims.

This invention relates to a grate b-ar lock, i. e., a device forpreventing displacement of the grate bars of a boiler, warm-air furnace,oven, or other heating apparatus utilizing rocking or tilting gratebars.

In the use of such apparatus, it frequently happens, on tilting of thebars for shaking or dumping the fuel bed, that clinkers wedging betweenadjacent bars tend to throw some of the bars 01T their bearings. Thereplacement of the bars is a tedious and diiicult task and numerousproposals have been made hertofore for preventing grate bars fromjumping oil their bearings. So far as I am aware, none of the previousproposals has entirely solved the problem and it is, therefore, anobject of this invention to improve generally upon grate bar locks asknown heretofore.

In a preferred embodiment of the invention, I provide a grate bar withan cverhanging end forming a concave pocket having a bearing surfaceadapted to engage one of a pair of trunnions extending inwardly from thewall of the combustion chamber. I also form a locking lug spacedvertically below the bearing surface adapted to engage the trunnion inthe event the grate bar tends to rise as in the case of the wedging ofclinkers between adjacent bars as above mentioned. The bearing surfacehas downward extensions which, with the locking lug, define throatsadapted to receive the trunnion in certain positions only of the bar.The trunnion is so shaped that it will not pass through the throat inany normal position of the grate bar.

. I also provide grate operating means for tilting a plurality of thegrate bars of a boiler furnace, such that the movement thereof isarrested before the grate bars are tilted to positions in which thethroats will pass the trunnions therethrough.

In modified embodiment, the concave pocket yproviding the trunnionbearing surface, and the locking lug are formed in the wall of thecombustion chamber and the trunnion integral With the grate bar.-

- The invention may be more fully comprehended by consideration of thefollowing detailed description and explanation with reference to theaccompanying drawings illustrating the preferred embodiment andmodification above mentioned. In the drawings,

,Figure 1 is a view showing a portion of the grate of a boiler furnacein plan with the wall ofthe combustion chamber in section on ahorizontalplane adjacent that of the grate;

Figure 2 is a transverse sectional view of a furnace showing a grate barin elevation;

Figures 3 and 4 are elevations showing the ends of the grate bar;

Figure 5 is a diagrammatic, partial, sectional View taken transverselythrough the grate bars, substantially along the plane of line V-V ofFigure 2;

Figure 6 is a similar View showing. the grate bars in alternatepositions and illustrating the manner in which the invention serves toprevent the grate bars from jumping oli;

Figure 'l is a similar view showing one grate bar tilted to abnormalposition for installation in or removal from the furnace;

Figure 8 is a view similar to Figure 5 showing a modification;

Figure 9 is a partial side elevation of the wall of a combustion chamberillustrating a further modification and showing the grate bar trunnionin section; and

Figure l0 is a partial sectional view taken along the plane of line X-Xof Figure 9.

Referring now in detail to the drawings and for the present, to Figures1 through 4, the combustion chamber of a boiler furnace is defined bythe lower limbs of arched, hollow, water sections l through which watercirculates to be heated. The sections are disposed side by side in theknown manner and alined holes therethrough connected by bushings II. Theboiler sections are supported on any convenient form of base panels (notshown).

Trunnions I2 extend inwardly from lower ends of the limbs of the boilersections and may be conveniently cast integrally therewith. The

trunnions I2 have convex upper bearing surfaces I3 and flat sides I4.The convex bearing surfaces I3 are adapted to be engaged by cooperatingconcave bearing surfaces formed on the ends of grate bars I5. As shownin Figure l, each boiler section is provided with trunnions supportingone grate bar whereby the number of sections and grate bars may bechosen to obtain the desired capacity. In some cases, however, aplurality of grate bars may be carried on a single boiler section. Thegrate bars I5 are elongated castings having an upper, fuel-supportingsurface with perforations I5' distributed thereover. In one end of thegrate bar, a recess or socket I is formed to receive one of thetrunnions I2. A crank arm I'I descends from the end of the grate bar inwhich the socket I6 is formed and terminates inla hook I8. A grateconnecting bar I9 has holes spaced therealong whereby it may be disposedover the hook ends of the crank arms I1 of the several grate bars andsupported thereby. Various means other than the hooks I8 may be used tohold the connecting bar in operative relation to the grate bars. One endof the bar is accessible from the front of the furnace and may beactuated by a manually operable lever to tilt the grate bars for shakingor dumping the fuel bed.

The end of each grate bar opposite that in which the socket IE isformed, is under-cut to form a pocket 2li having a concave bearingsurface 2l, It will be understood that the term under-cut is used todefine merely the contour of the end of the bar and not the method ofshaping it. The bearing surface 2l rests on the convex upper surface ofone of the trunnions I2, thereby permitting tilting movement of thegrate bar as described above. The wall of the pocket 2i) has downwardextensions 22 for a purpose which will appear shortly.

A locking lug 23 extends outwardly from the under-cut end of thegratebar and` is disposed centrally below the bearing surface 2l by adistance slightly greater than the vertical dimension of the trunnionI2. The lower surfaces of the trunnions are rounded convexly as at 24and lug 23 has its upper end shaped to conform therewith as indicated atThe extensions 22 of the walls of pocket 2t form, with the lug 23, slotsor throats 26 leading from both sides of the grate bar toward thebearing surface 2l. The sides of the lug 2S are generally parallel tothe `extensions 22. The throats 2t are dimensioned by suitably shaping'and spacing the extensions 22 and the lug 23, to pass the trunnions I2only when the grate bar is tilted to a position making a greater anglewith the horizontal than is made by the bar in any normal operatingposition thereof.

The operation of the grate bar lock will now be explained by referenceto Figures 5 through 7. Figure 5 illustrates the normal position of thegrate bars. In such position, the lugs 23 would engage the trunnions I2should the grate bars tend to be lifted up. When the bars are tilted tothe positions shown in Figure 6 in shaking the fuel bed, the cooperativerelation of the locking lug and the trunnions is maintained so thatshoulda piece of fuel or clinker such as indicated at 27, become wedgedbetween the adjacent bars, it would be impossible for one bar to bethrown olf its bearing at the end opposite that from which the crank ildepends.

As shown in Figure 6, any tendency to lift the grate bar at the leftwhen returning the bars to horizontal position, would be resisted byengagement of the lug 23 with the adjacent trunnicn. It is further to benoted that Figure 6 illustrates the extreme position to which the gratebar may be shifted by actuating the connecting bar I5. This results fromengagement of the bar i8 with the under-surface of the grate bars,thereby arresting the connecting bar before the grate bars reach suchposition that they can be lifted off the trunnions I2 as will now beexplained,

Figure 7 illustrates the position to which the grate bars must beshifted for installation or removal. To insert a grate bar, the socketi6 thereof is rst disposed on one of the trunnions I2. Before placingthe connecting bar t9' in position, the grate bar is tilted to theposition indicated in Figure 7 in which the throat 26- will admit thetrunnions between the extension 22 and the lug 23. Such arcuate movementof the bar may be necessary to cause proper entry of the trunnions intothe slot or throat, but this is a matter presenting no difficulty. Whenall the bars have been positioned 'as indicated, the connecting bar maybe disposed over the hook ends I8 of the cranks II of al1 grate bars.

As explained above, after the grate bars have been installed and theconnecting bar placed in position, the grate bars are prevented fromjumping off the trunnions at the ends opposite those in which thesockets I6 are formed. It is a simple matter, however, to remove any onegrate bar should that be necessary, for repair or replacement. Theconnecting bar I9 is first removed and the grate bar to be replaced istilted to an angular position such as illustrated in Figure 7. In thatposition, the end of the grate bar opposite that in which the socket I6is formed, may be raised with slight angular movement so that. thethroat 26 clears the trunnion I2. When the grate bar has cleared thetrunnion, it may be moved axially off of the other trunnion. Aspreviously explained, the locking lugs 23 prevent lifting of the gratebars at one end. The socket I6, obviously, prevents lifting of the barsat their other end.

The grate bar lock. described above is such as to permit end-to-endreversal of the grate bar. By the provision of the tapered throat 26leading downwardly of the lug 23, the grate barl may be, installed orremoved by tiltin-g it in the same direction regardless of whether thecrank is at one end or the other. This is quite adl vantageous,particularly in large boilers where;

it is customary to provide two shaking levers at the front of thefurnace, each lever operating a connecting bar cooperating with thecranks of half the grate bars. Where the possibility of positioning thegrate bars in either direction is not important, I may employ theconstruction shown in Figure 8, which is similar to that described abovein allv respects except that only one extension 22 and one throat 26 areprovided, the locking lug 23' being continuous with the over-hangingwall of the pocket 2li.

A further modification of the invention which is the result of a merereversal of the trunnions, is illustrated in Figures 9 and 10. As thereshown, the wall of the combustion chamber 3l which may be the inner wallof a hollow boiler section such as that shown. in Figure 1i), isprovided with a rib 32 integral therewith and providing a concavebearing surface 33 adapted. to. receive a trunnion 34 formed at one endof a grate bar 35. The other` end of 'the bar is supported in the samemanner as in the case of the bars I5. The rib 32 has extensions 3S. Itwill be apparent that the rib 32 provides a pocket similar to that shownat 20 in the end of the` grate bar I except that itis inverted. Alocking lug 3l is4 also formed integral with the wall: 3l and is locatedcentrally of the rib 32 and spaced thereabove. The trunnion 36 has flatvsides like the trunnions l2 and the extensions 3bA cooperate with thelug 37 to define slots or throats 38 through which the trunnion Sil maybe passed when the grate bar is tilted to an angl@ beyond that to whichit is actuated in the normal tilting movement incident to shaking ordumping. The grate bai 35 is installed and removed in the same manner asalready described for the bars I5.

It. will be apparent that the invention is characterized by numerousadvantages. The structure providing a lock for preventing the grate barfrom jumping 01T its bearing, is simple and inexpensive. The lock isequally effective whether the4 bar is in its normal or horizontalposition, or is tilted for shaking or dumping. Any bar may easily beremoved, nevertheless, without disturbing the others. The accidentalmovement of the grate bar past the locking position is prevented sincemovement of the grate connecting bar is arrested before the grate barshave been tilted too far. The reversibility of grate bars provided withmy lock has already been mentioned. This is a further advantage in thatit is not necessary to stock different bars having cranks at the lefthand and right hand ends. A further advantage is that the grate bar lockdoes not reduce the area of the rounded upper bearing surface of thetrunnions supporting the grate bar. rI'his bearing surface conforms tothe contour of-concave pocket at the end of the grate bar and has anextensive area of contact therewith. As previously stated, furthermore,the locking lugs may be integral with the grate bar, thus avoiding thenecessity for any additional manufacturing operations.

While I have shown the grate bar lock of my invention at only one end ofthe bar, it may also be formed at both ends if desired, or on the endopposite that on which it is illustrated. Similarly, as shown in thedrawings, trunnions may be formed on the grate bar and cooperate with abearing surface in a concave pocket formed on the wall of the boilersection.

Since the grate bar lock is eiective when the bars are in their normalposition, it is impossible to dislodge a grate bar while working thefuel bed with a poker or splice bar.

While I have illustrated and described but a preferred embodiment of theinvention with slight modifications, it will be recognized that changesin the construction and arrangement disclosed may be made withoutdeparting from the spirit of the invention or the scope of the appendedclaims.

I claim:

l. In a grate, pairs of spaced supports, a grate bar tiltable on cachpair of supports, and locking means comprising a portion of the baroverhanging one end thereof and forming a concave pocket having abearing surface engaging one of said supports, a locking lug on the barspaced below said surface and normally adapted to engage saidlast-mentioned support should the bar tend to rise, said one of saidsupports having flat sides and a convex top engaging said surface, saidsurface and lug being spaced sufficiently to clear said one of saidsupports only when the bar is tilted through an angle greater than thatthrough which it is turned for normal shaking and dumping, and movedgenerally parallel to said sides.

2. In a grate, a plurality of bars, trunnions tiltably supporting thebars, each bar having a portion overhanging at one end to provide apocket with a concave bearing surface adapted to engage a supportingtrunnion, said surface having a downwardly inclined extension, and alocking lug on said bar spaced below said surface, the side of the lugadjacent the extension being generally parallel thereto, said lug andsaid extension dening a slot adapted to admit said trunnion, saidtrunnion being shaped oblong in cross-section to clear said slot onlywhen the bar is tilted to a position beyond its extreme normal operatingpositions.

3. In a grate, pairs of spaced trunnions, a grate bar tiltable on eachpair of trunnions, one end of said grate bar having an overhangingportion providing a pocket on which a trunnion-engaging surface isformed, the trunnion engaged by the surface of said pocket having agreater dimension vertically than horizontally, and a throat extendingat an angle from said pocket dimensioned to clear said last-mentionedtrunnion only when the grate bar is tilted to a position beyond thelimits of its normal tilting movement.

4. In a tilting grate bar, locking means for preventing jumping of thebar from its normal position relative to a furnace wall comprising anoverhanging shoulder at one end of the bar providing a bearing surfaceconcave downwardly, said surface being adapted to engage a pivotalsupport rounded on top but having a greater dimension vertically thanhorizontally, and a locking lug on said end of the bar spaced below saidsurface, having generally flat sides and projecting beneath saidsupport, said surface having a downwardly inclined extension definingwith the adjacent side of the lug a throat adapted to clear the width ofthe support when said end of the bar is raised relative thereto, onlyafter the bar has been tilted through an angle greater than that throughwhich it is tilted for normal shaking and dumping.

JOHN W. HALL.

